Britney Spears entered a rehab center this week, according to the celebrity news show "Extra." However, TMZ.com is reporting that Spears has already left the facility.

According to TMZ.com, the pop star entered rehab at the urging of her family and friends, who were concerned about her hard-partying ways, but refused to stay.

Spears' spokesperson told Access Hollywood, however, that the mother of two is not in rehab, telling Access, "totally untrue. She is not in rehab. No way."

Since filing for divorce from Kevin Federline in November, Spears has drawn criticism for her drinking, partying and sloppy appearance. Spears recently has been photographed intoxicated at nightclubs and was carried out of a Las Vegas club on New Year's Eve after collapsing. Reps for the star blamed the collapse on exhaustion.

Earlier this week, MSNBC.com's
Jeannette Walls reported in the Scoop
that a former assistant of Spears' had written on a gossip blog that the singer was headed for "rock bottom" and in need of help.

An e-mail from Britney Spears' former assistant Felicia Culotta saying the 25-year-old pop star needs to get her act together because she's headed for "rock bottom" has been posted on a Web site's gossip blog.

Slideshow: The week in celebrity sightings
"I cherish ALL the incredible opportunities that came my way thru my job with Britney and am crushed/saddened/heart sick by the way her life is unfolding," said the posting by Felicia Culotta on ThatOtherBlog, a gossip blog on the Hollywood.com Web site.

The e-mail, addressed to "Ruben," was sent in response to an editorial "Why Britney Is Asking for It," according to the blog.

"I want you to know Ruben that WE (as in her Family and nearest and dearest — ALL of whom are not on the payroll anymore!!) are doing EVERYTHING in our power to get help for Britney," writes Culotta, who says she worked for Spears for nearly 10 years.

"Ruben," who runs ThatOtherBlog, told The Associated Press on Friday that Culotta is a good friend and that he is declining media requests to interview her. In her e-mail, Culotta said she is working as a corporate flight attendant and living in Mississippi.

Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.